Data Acquisition Systems and Instruments - Insights

Results of a Poll of Engineering360 subscribers

Data acquisition systems and instruments are either the combination of a number of data acquisition components that make up a complete system or a self-contained instrument. They are used to collect, digitize, and process multiple sensor or signal inputs for the purpose of monitoring, analyzing, and/or controlling systems and processes. Data acquisition systems and instruments are configured in a wide variety of instrumentation and modular systems. Applications include manufacturing testing of...
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Q & A on Data Acquisition Systems and Instruments

We asked our users for their input on Data Acquisition Systems and Instruments.
Here are the results of 184 users
familiar with Data Acquisition Systems and Instruments.

Do you know of any disastrous mistakes that occurred due to the incorrect usage of data acquisition systems and instruments?

14 answers

Answers:

* Numerous issues with software.
* Sampling rate vs Hz as in (9).
* In one radio telemetry application the transmitted timebase was not accurate - not helpful for vibration measurement.
* Software can have obscure lower level menu settings.

~Rod M., Engineering Consultant, Auckland, New zealand

Anything that is purchased without a good idea of the cost throughout the life of the system. Having to buy something after 4-5 years service because of obsolescense is very expensive and disastrous especially if one cannot access data.

~Gary G, Business Development, Wellington, OH

Voltage, Amps, bang ?? ALWAYS use one of those little boxes that tell you how much amps and volts are coming out of that little wire. just because it looks like a 5volt analogue sensor ...

~Michael D, Data engineer, Amersfoort, Netherlands

Yes, inadequate calibration and bookkeeping. It costs lots of money as the receiver will not pay the merchandise if calibration is not done properly and in time.

~Paul D, Engineer, Duketown, Netherlands

If Interfaces are not properly understood & designed & interconnect the system with devices, it may end up with serious consequences.

~Uttiramerur PADMANABHAN, Consultant, Bangalore;, India

A smelter plant was forced to shutdown due to failure of the data acquisition system.

Standardization around usb and usb cards (eg SD card) and mobile phone technology. USB stick style loggers with options to change the sensor head. Ability to use a mobile phone to collect or view data either by blue tooth, or wifi or directly (by physically connecting). To use mobile phone to reset and program loggers. Ability for logger to connect to either internet/mobile network via modem (these fit in usb stick now) OR using a mobile phone. Ability to call a number and transmit data (maybe as an extended sms?) at a predetermined interval. If connected to mobile network then the logger can be called and interrogated remotely. I have seen kits for a remote web server in electronic magazines where the user can interact with the remote system. Option for USB style system described above to have a sensor device that can be connected to the logger remotely either by wire or by blue tooth/wifi. If by blue tooth one logger could then support multiple sensor units. This would be great for chemistry sensors in environmental studies (provided the sensor is low power). System to have water resistant and water proof options. System to have remote/auxillary power input (12V battery or solar). It would be nice to also have options/support for cameras. A further extension would be GPS support. And finally it would be really great if a trigger level could be set on inputs that activated an output (or multiple outputs). For example when the trigger level on a depth gauge reaches a certain level (eg river in flood) an output triggers a message to the researcher OR triggers a device to collect samples OR ... As cheap as possible. Given everything mentioned above except for the sensors is mass produced... Not much to ask is it? ;-)

~Shane P, Lecturer/Researcher, Makassar, Indonesia

RaceLogic have already introduced predictive lap timing for their entry-level loggers. I am very innovation focused and they trumped me on that one, so I'm a little short of ideas at the moment. It'll come back, though! Oh yes, 100Hz instead of 10Hz would be (very) nice.

Do you have any advice for people relative to buying or using data acquisition systems and instruments?

20 answers

Answers:

For motorsports: start with video and frame counting. If you how to extract info from that source, you'll be able to extract more from your DAS. Otherwise you''ll be driving around with a fashionable automotive accessory.

~Michael D, Data engineer, Amersfoort, Netherlands

For buying - confirm on sampling rates, resolution, isolation between channels, input voltage ranges
For using - Periodic calibration of system will help in the quality of data measured

~RAJESH GABRIEL, Marketing/Sales, CHENNAI, INDIA

Know your system and determine what it is you would like to get out of it. Then Research it with existing applications.

~Daniel R., Technical Support, Lewiston, ME

Think before you begin, and once started keep thinking
Make sure you have established and understood the requirements

~Rudolf LP, University Lecturer, Leiden, The Netherlands

Look into the market for available option, if not design your own or hire an engineering contractor.

~Juanito M, Systems Project Leader, Dubai, UAE

Also look at available software data processing and reporting capabilities for your instruments.

Is there any advice you want to share with users to help them avoid common errors in selection or usage of data acquisition systems and instruments?

22 answers

Answers:

How hard do you want to win? That's the key to how much money you want to invest. And start off simple and upgrade. Entry level loggers are cheap nowadays and can sometimes be run off an iPhone or Android phone. Once you've mastered a certain system and want more, upgrade. That way you'll arrive at the system that feeds your needs in the most efficient manner. Too complex and it will end up in a corner never to be used again!

~Michael D, Data engineer, Amersfoort, Netherlands

Short list the possible candidates. Do the following for each prospective product: Study the options and specially the maximum and minimum ratings of the system. If possible visit the site where the product has been installed and observe the product performance. Ask the users how they feel about the product.

~Juanito M, Systems Project Leader, Dubai, UAE

Hardware is typically updated within 5 years. Choose something that can be updated technologically without buying a new system. Look at the history of the products offered 5 years ago versus today. Ask yourself, Can I use those with the present equipment?

~Gary G, Business Development, Wellington, OH

Be aware of the distinction between the sampling rate [samples per second] and the frequency response [Hz]. The sampling rate would normally need to be much higher than the desired frequency response, but some manufacturers give the sampling rate in Hz.

~Rod M., Engineering Consultant, Auckland, New zealand

Read carefully all technical data of equipment. For example some telemetry measuring systems work at approximately 900 MHz. This is the working frequency of European cell phones. It's possible to have terrible experiences.

~Svetlozar Y, Research & Development, Varna, Bulgaria

Type of sensors should be as per specific application e.g. working temperature, stability and repeatability, mounting of sensors.

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